Constitutive expression of the proteorhodopsin gene by a flavobacterium strain representative of the proteorhodopsin-producing microbial community in the North Sea.

ABSTRACT: Proteorhodopsin (PR), a photoactive proton pump containing retinal, is present in approximately half of all bacteria in the ocean, but its physiological role is still unclear, since very few strains carrying the PR gene have been cultured. The aim of this work was to characterize PR diversity in a North Sea water sample, cultivate a strain representative of North Sea PR clusters, and study the effects of light and carbon concentration on the expression of the PR gene. A total of 117 PR sequences, of which 101 were unique, were obtained from a clone library of PCR-amplified PR gene fragments. Of the North Sea PRs, 97% were green light absorbing, as inferred from the amino acid at position 105; 67% of the PR protein fragments showed closest similarity to PRs from Alphaproteobacteria, 4% show

SUBMITTER: Riedel T 

PROVIDER: S-EPMC2869143 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature